they lay 20, 30 eggs and the sex of the alligator is determined by the heat of the nest. >> male is hot. >> a real hot nest, the eggs will be males. the gator also, we found, did research, we found boards, cans, tubes, everything inside these creatures. because when they get hungry they will take apart anything. >> ever found human remains inside of curly? >> no. but i've done shows in malaysia where you wouldn't believe, the crocodiles get to be 21, 22, 23, 24 feet long, over 2,000 pounds. you're talking about something much bigger than your stage here. >> i think we should go quickly to commercial break. >> you want to hold it? >> i don't want to hold curly, no. no. i think we're into a no touching zone on this show. when we come back, you will show us happy feet penguins and one of the oldest animals in the world. first, here's one of jack's top five animal close encounters. >> what are you doing? >> i'm demonstrating how the eyes are fixed on movement.